The invention relates to a device for correcting the differential distortion resulting from simultaneous observation of a field of view at two distinct locations through a transparent shield in a given spectral band, which shield has a shape generating a distortion without rotational symmetry, when the images received by a first and a second receiver sensitive in the spectral band and arranged each at one of the locations are superimposed.
Numerous sighting or registering devices (CCD camera, vidicon) on board airplanes must take the presence of a cockpit window into account whose shape (for example, conical) distorts the view of the landscape: an airplane on a test flight, for example is equipped with a video camera whose image is recaptured by means of a goggle at eye level in order to be superimposed on the image received by the pilot's eye. Since this camera cannot be placed near the pilot's head, the distortion introduced by the cockpit window is not the same to the pilot's eye and the camera because the optical beams traverse the cockpit window at different heights, which creates deviations of an asymmetrical nature. These deviations may be quite considerable (of the order of one degree): it is thus necessary to correct or at least reduce them. In certain cases an electronic correction by means of digital processing of the image entails complex and bulky systems.